THERE was an anxious moment when Kate Middleton, the Duchess of Cambridge, appeared in her immaculately fitting, vermilion red Alexander McQueen dress and James Lock hat, tilted at what is emerging as the Duchess's favourite angle (who knew you could have a signature incline?). She looked stunning... and bright.

THERE was an anxious moment when Kate Middleton, the Duchess of Cambridge, appeared in her immaculately fitting, vermilion red Alexander McQueen dress and James Lock hat, tilted at what is emerging as the Duchess's favourite angle (who knew you could have a signature incline?). She looked stunning... and bright.

Too bright? Would she outshine the woman whose day this undoubtedly was? Was this Kate's first faux pas?

But at 2.10, Queen Elizabeth II appeared and the fashion world breathed once more.

Wearing her signature -- coat and dress -- the queen shimmered in ivory boucle against those louring skies.

The gold and silver embroidered spots and Swarovski crystals may not have dazzled in the shafts of sun that were meant to be bouncing off the rippling Thames as intended, but she certainly wasn't going to be outshone by anyone, even if, for a few more worrying seconds, the Royal Handbag appeared to be rashly gaping open.

For weeks, there had been speculation about what colour the queen would wear. She doesn't often sport red these days, and in any case it would have clashed catastrophically with those velvet thrones (shades of the Beckhams there in a rare mis-step).

Options were narrowing. In the end there could only be one. It's not just that ivory is quintessentially, understatedly luxurious (all that dry cleaning), but it's extremely flattering without being mother-of-the-bride. It also brought to mind her coronation day, when she pledged herself to the lifelong service of her kingdom.

Once we saw the queen, we knew there was method in Kate's scarlet. It would only be a matter of time before someone turned up in blue. Sure enough, Princess Anne and Pippa Middleton did the duties in navy. With the Duchess of Cornwall wearing an elegant cream coat and dress by Anna Valentine and a Philip Treacy hat, this promised to be the most meticulously colour-co-ordinated Royal photograph ever.

However sprucely turned out the other royals looked, sartorially -- as in every way -- it was the queen's day.

"It is hard to imagine a different outfit that the queen could have sported better," Karl Lagerfeld tweeted.

The matching coat and dress, designed by Angela Kelly, the queen's senior dresser, were made in a cosy wool. It wasn't all pragmatism, though. That single organza frill on her coat was purely decorative, as were the dashing feathers on that hat.

But function is never far away in the monarch's choices. That brim was broad enough to keep the worst of any downpour at bay, but not melodramatically wide.

And, naturally, it was all richly emblematic. The outfit included allusions to her three jubilees as well as a reference to her distant ancestor Elizabeth I, who wore a Tudor, farthingaled version in the Ditchley portrait. Angela Kelly says that over the years the queen has taught her a huge amount about regal symbolism. The outfit was, apparently, a year in the planning.

So the sun didn't shine on the anniversary of her 60th reign. But those chilly blasts at least meant that none of the younger royals turned up in inappropriately skimpy cocktail wear.